U.S. patent application number 16/515835 was filed with the patent office on 2020-01-23 for display device having touch sensor.
This patent application is currently assigned to LG DISPLAY CO., LTD.. The applicant listed for this patent is LG DISPLAY CO., LTD.. Invention is credited to Hyang-Myoung GWON, Ji-Hyun JUNG, Jae-Gyun LEE, Ru-Da RHE.
Application Number | 20200026377 16/515835 |
Document ID | / |
Family ID | 67438183 |
Filed Date | 2020-01-23 |
United States Patent
Application |
20200026377 |
Kind Code |
A1 |
GWON; Hyang-Myoung ; et
al. |
January 23, 2020 |
DISPLAY DEVICE HAVING TOUCH SENSOR
Abstract
The present disclosure provides a display device having a touch
sensor for securing improved touch-sensing performance. The display
device having a touch sensor includes a touch-driving circuit
configured to drive a touch-driving line and a touch-sensing line,
which are disposed on an encapsulation unit covering a
light-emitting element, in a mutual-capacitance mode and to drive
at least one of the touch-driving line or the touch-sensing line in
a self-capacitance mode, and the touch-driving circuit supplies a
load free driving signal to a shield line overlapping the
touch-driving line and the touch-sensing line, thereby securing
improved touch-sensing performance.
Inventors: |
GWON; Hyang-Myoung;
(PAJU-SI, KR) ; JUNG; Ji-Hyun; (PAJU-SI, KR)
; RHE; Ru-Da; (SEOUL, KR) ; LEE; Jae-Gyun;
(PAJU-SI, KR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
LG DISPLAY CO., LTD. |
Seoul |
|
KR |
|
|
Assignee: |
LG DISPLAY CO., LTD.
Seoul
KR
|
Family ID: |
67438183 |
Appl. No.: |
16/515835 |
Filed: |
July 18, 2019 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G06F 2203/04112
20130101; G06F 3/0412 20130101; G06F 3/0443 20190501; G06F
2203/04107 20130101; G06F 2203/04102 20130101; G06F 2203/04111
20130101; G06F 3/044 20130101; G06F 3/0446 20190501; G06F 3/04182
20190501 |
International
Class: |
G06F 3/044 20060101
G06F003/044; G06F 3/041 20060101 G06F003/041 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 19, 2018 |
KR |
10-2018-0084291 |
Claims
1. A display device comprising: a display panel comprising a
light-emitting element disposed on a substrate, a touch-driving
line and a touch-sensing line disposed on the substrate, and a
shield line overlapping the touch-driving line and the
touch-sensing line; and a touch-driving circuit configured to drive
the touch-driving line and the touch-sensing line in a
mutual-capacitance mode and to drive at least one of the
touch-driving line or the touch-sensing line in a self-capacitance
mode, wherein the touch-driving circuit supplies a load free
driving signal to the shield line, at least one of a phase or an
amplitude of the load free driving signal being same as a phase or
an amplitude of a touch-driving signal of the self-capacitance mode
to be supplied to at least one of the touch-driving line or the
touch-sensing line.
2. The display device according to claim 1, wherein the shield line
comprises: a shield-driving line disposed along the touch-driving
line to overlap the touch-driving line; and a shield-sensing line
disposed along the touch-sensing line to overlap the touch-sensing
line.
3. The display device according to claim 2, wherein, in the
mutual-capacitance mode, the touch-driving circuit senses a
variation in mutual capacitance through the touch-sensing line by
supplying a first touch-driving signal to the touch-driving line,
and electrically connects the shield-driving line to the
touch-driving line or floats the shield-driving line.
4. The display device according to claim 3, wherein, in the
self-capacitance mode, the touch-driving circuit senses a variation
in self-capacitance of at least one of the touch-driving line or
the touch-sensing line by supplying a second touch-driving signal
to at least one of the touch-driving line or the touch-sensing
line, and supplies the load free driving signal to at least one of
the shield-driving line or the shield-sensing line.
5. The display device according to claim 2, wherein the
self-capacitance mode and the mutual-capacitance mode are
alternately driven, wherein the self-capacitance mode comprises a
first self-capacitance mode and a second self-capacitance mode, the
first self-capacitance mode and the second self-capacitance mode
being driven in that order or in a reverse order,
6. The display device according to claim 5, wherein, in the first
self-capacitance mode, the touch-driving circuit supplies the
second touch-driving signal to the touch-driving line and supplies
the load free driving signal to the shield-driving line, and
wherein, in the second self-capacitance mode, the touch-driving
circuit supplies the second touch-driving signal to the
touch-sensing line and supplies the load free driving signal to the
shield-sensing line.
7. The display device according to claim 6, wherein, in the first
self-capacitance mode, the touch-driving circuit supplies a ground
voltage to the touch-sensing line and the shield-sensing line, and
wherein, in the second self-capacitance mode, the touch-driving
circuit supplies a ground voltage to the touch-driving line and the
shield-driving line.
8. The display device according to claim 2, wherein the
shield-driving line comprises a plurality of shield-driving
electrodes disposed on an encapsulation unit in a first direction,
and a first shield bridge connecting the shield-driving electrodes
to each other, and wherein the shield-sensing line comprises a
plurality of shield-sensing electrodes disposed in a same plane as
the shield-driving electrodes in a second direction, and a second
shield bridge connecting the shield-sensing electrodes to each
other.
9. The display device according to claim 8, wherein the
touch-driving line comprises a plurality of touch-driving
electrodes disposed on a touch insulation film in the first
direction, and a first touch bridge connecting the touch-driving
electrodes to each other, the touch insulation film being disposed
on the shield-driving electrodes, and wherein the touch-sensing
line comprises a plurality of touch-sensing electrodes disposed in
a same plane as the touch-driving electrodes in the second
direction, and a second touch bridge connecting the touch-sensing
electrodes to each other.
10. The display device according to claim 2, further comprising: an
encapsulation unit disposed to cover the light-emitting element; a
touch-routing line connected to each of the touch-sensing line and
the touch-driving line disposed on the encapsulation unit; and a
shield-routing line connected to each of the shield-sensing line
and the shield-driving line disposed on the encapsulation unit,
11. The display device according to claim 10, wherein each of the
touch-routing line and the shield-routing line is disposed along a
side surface of the encapsulation unit.
12. The display device according to claim 10, further comprising: a
shield pad connected to the shield-routing line, the shield pad
being disposed on the substrate exposed by the encapsulation unit;
and a touch pad connected to the touch-routing line, the touch pad
being disposed adjacent to the shield pad.
13. The display device according to claim 12, wherein the substrate
is foldable or bendable.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims the priority benefit of Korean
Patent Application No. 10-2018-0084291, filed in the Republic of
Korea on Jul. 19, 2018, the disclosure of which is hereby
incorporated by reference as if fully set forth herein.
BACKGROUND OF THE INVENTION
Field of the Invention
[0002] The present invention relates to a display device, and more
particularly to a display device having a touch sensor for securing
improved touch-sensing performance.
Discussion of the Related Art
[0003] A touch sensor is an input device through which a user can
input a command by selecting instructions displayed on a screen of
a display device using a hand or an object. That is, the touch
sensor converts a contact position that directly contacts a human
hand or an object into an electrical signal and receives selected
instructions based on the contact position as an input signal. Such
a touch sensor can substitute for a separate input device that is
connected to a display device and operated, such as a keyboard or a
mouse, and thus the range of application of the touch sensor has
continually increased.
[0004] In the case in which a touch sensor is disposed on a display
device, parasitic capacitance is formed at a region at which the
conductive layers of the display device and the touch sensor
overlap each other. This parasitic capacitance increases a
touch-driving load and deteriorates touch-sensing accuracy. In
particular, the shorter the distance between the conductive layer
of the display device and the touch sensor, the larger the
parasitic capacitance, which makes it difficult to ensure
touch-sensing performance.
SUMMARY OF THE INVENTION
[0005] The present invention is directed to a display device having
a touch sensor that substantially obviates one or more problems due
to limitations and disadvantages of the related art.
[0006] An object of the present invention is to provide a display
device having a touch sensor for securing improved touch-sensing
performance.
[0007] Additional advantages, objects, and features of the
invention will be set forth in part in the description which
follows and in part will become apparent to those having ordinary
skill in the art upon examination of the following or can be
learned from practice of the invention. The objectives and other
advantages of the invention can be realized and attained by the
structure particularly pointed out in the written description and
claims hereof as well as the appended drawings.
[0008] To achieve these objects and other advantages and in
accordance with the purpose of the invention, as embodied and
broadly described herein, a display device having a touch sensor
includes a touch-driving circuit configured to drive a
touch-driving line and a touch-sensing line, which are disposed on
an encapsulation unit covering a light-emitting element, in a
mutual-capacitance mode and to drive at least one of the
touch-driving line or the touch-sensing line in a self-capacitance
mode, and the touch-driving circuit supplies a load free driving
signal to a shield line overlapping the touch-driving line and the
touch-sensing line, thereby securing improved touch-sensing
performance.
[0009] It is to be understood that both the foregoing general
description and the following detailed description of the present
invention are exemplary and explanatory and are intended to provide
further explanation of the invention as claimed.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] The accompanying drawings, which are included to provide a
further understanding of the invention and are incorporated in and
constitute a part of this application, illustrate embodiment(s) of
the invention and together with the description serve to explain
the principle of the invention. In the drawings:
[0011] FIG. 1 is a perspective view illustrating a display panel
having a touch sensor according to an example of the present
invention;
[0012] FIG. 2 is a cross-sectional view taken along line I-I' in
the display panel having a touch sensor illustrated in FIG. 1;
[0013] FIG. 3 is a plan view illustrating the touch sensor
illustrated in FIG. 1 in detail;
[0014] FIG. 4A is a cross-sectional view taken along line II-II' in
the display device having a touch sensor illustrated in FIG. 3,
FIG. 4B is a cross-sectional view taken along line III-III' in the
display device having a touch sensor illustrated in FIG. 3, FIG. 4C
is a cross-sectional view taken along line IV-IV' in the display
device having a touch sensor illustrated in FIG. 3, and FIG. 4D is
a cross-sectional view taken along line V-V' in the display device
having a touch sensor illustrated in FIG. 3;
[0015] FIG. 5 is a view illustrating a touch-driving circuit for
driving the touch sensor according to an example of the present
invention;
[0016] FIGS. 6A to 6C are views illustrating a mutual-capacitance
mode and a self-capacitance mode according to an example of the
present invention in detail;
[0017] FIG. 7 is a waveform diagram illustrating a control signal
for selecting a display mode and a touch-sensing mode of the
display device having a touch sensor according to an example of the
present invention; and
[0018] FIG. 8 is a waveform diagram illustrating the signal
waveform to be supplied to a touch electrode and a shield electrode
in a touch-sensing mode of the display device having a touch sensor
according to an example of the present invention.
DETAILED DESCRIPTION OF THE EMBODIMENTS
[0019] Reference will now be made in detail to exemplary
embodiments of the present invention, examples of which are
illustrated in the accompanying drawings. Wherever possible, the
same reference numbers will be used throughout the drawings to
refer to the same or like parts.
[0020] FIG. 1 is a perspective view illustrating an organic
light-emitting display device having a touch sensor according to an
example of the present invention. All the components of the organic
light-emitting display device according to all embodiments of the
present invention are operatively coupled and configured.
[0021] The organic light-emitting display device having the touch
sensor illustrated in FIG. 1 includes a plurality of subpixels
arranged in a matrix form on the substrate 111, an encapsulation
unit 140 disposed on the subpixels, touch sensors TX and RY
disposed on the encapsulation unit 140, and shield electrodes SX
and SY disposed between the encapsulation unit 140 and the touch
sensors TX and RY.
[0022] The organic light-emitting display device having the touch
sensor has an active area disposed on a substrate 111 and a
non-active area disposed adjacent to the active area. The substrate
111 is formed of a flexible material such as plastic or glass to be
foldable or bendable. For example, the substrate 111 is formed of
polyimide (PI), polyethylene terephthalate (PET), polyethylene
naphthalate (PEN), polycarbonate (PC), polyethersulfone (PES),
polyacrylate (PAR), polysulfone (PSF), or cyclic-olefin copolymer
(COC).
[0023] The active area displays an image through unit pixels
arranged in a matrix form. Each unit pixel includes red, green and
blue subpixels, or includes red, green, blue, and white
subpixels.
[0024] Each of the subpixels includes, as illustrated in FIG. 2, a
pixel-driving circuit, including a plurality of thin-film
transistors 130, and a light-emitting element 120 connected to the
pixel-driving circuit.
[0025] Each of the driving thin-film transistors 130 included in
the pixel-driving circuit controls the current supplied from a
high-voltage supply line to the light-emitting element 120 in
response to a data signal supplied to a gate electrode of the
corresponding driving thin-film transistor 130, thus adjusting the
amount of light emitted from the light-emitting element 120.
[0026] Such a driving thin-film transistor 130, as illustrated in
FIG. 2, includes a semiconductor layer 134 disposed on a buffer
layer 104, a gate electrode 132 overlapping the semiconductor layer
134 with a gate insulation film 102 interposed therebetween, and
source and drain electrodes 136 and 138 formed on an interlayer
insulation film 114 so as to come into contact with the
semiconductor layer 134. Here, the semiconductor layer 134 is
formed of at least one of an amorphous semiconductor material, a
polycrystalline semiconductor material, or an oxide semiconductor
material.
[0027] The light-emitting element 120 includes an anode 122, at
least one light-emitting stack 124 formed on the anode 122, and a
cathode 126 formed on the light-emitting stack 124.
[0028] The anode 122 is electrically connected to the drain
electrode 138 of the driving thin-film transistor 130, which is
exposed through a pixel contact hole penetrating a protective film
116 and a pixel planarization layer 118.
[0029] The light-emitting stack 124 is formed on the anode 122 in a
light-emitting area that is defined by the bank 128. The
light-emitting stack 124 is formed by stacking a hole-related
layer, an organic emission layer, and an electron-related layer on
the anode 122 in that order or in the reverse order. In addition,
the light-emitting stack 124 can include first and second
light-emitting stacks, which face each other with a charge
generation layer interposed therebetween. In this case, the organic
emission layer of any one of the first and second light-emitting
stacks generates blue light, and the organic emission layer of the
other one of the first and second light-emitting stacks generates
yellow-green light, whereby white light is generated via the first
and second light-emitting stacks. Since the white light generated
in the light-emitting stack 124 is incident on a color filter
located above or under the light-emitting stack 124, a color image
can be realized.
[0030] In addition, colored light corresponding to each subpixel
can be generated in each light-emitting stack 124 in order to
realize a color image without a separate color filter. That is, the
light-emitting stack 124 of the red subpixel can generate red
light, the light-emitting stack 124 of the green subpixel can
generate green light, and the light-emitting stack 124 of the blue
subpixel can generate blue light.
[0031] The cathode 126 is formed so as to face the anode 122 with
the light-emitting stack 124 interposed therebetween and is
connected to a low-voltage supply line.
[0032] The encapsulation unit 140 can prevent external moisture or
oxygen from permeating the light-emitting element 120, which is
vulnerable to external moisture or oxygen. To this end, the
encapsulation unit 140 includes at least one inorganic
encapsulation layer 142 and at least one organic encapsulation
layer 144. In the example(s) of the present invention, the
structure of the encapsulation unit 140 in which the first
inorganic encapsulation layer 142, the organic encapsulation layer
144 and the second inorganic encapsulation layer 146 are stacked in
that order will be described by way of example.
[0033] The first inorganic encapsulation layer 142 is formed on the
substrate 111, on which the cathode 126 has been formed. The second
inorganic encapsulation layer 146 is formed on the substrate 111,
on which the organic encapsulation layer 144 has been formed, so as
to cover the upper surface, the lower surface and the side surface
of the organic encapsulation layer 144 together with the first
inorganic encapsulation layer 142.
[0034] The first and second inorganic encapsulation layers 142 and
146 minimize or prevent the permeation of external moisture or
oxygen into the light-emitting stack 124. Each of the first and
second inorganic encapsulation layers 142 and 146 is formed of an
inorganic insulation material that is capable of being deposited at
a low temperature, such as silicon nitride (SiNx), silicon oxide
(SiOx), silicon oxide nitride (SiON), or aluminum oxide
(Al.sub.2O.sub.3). Thus, since the first and second inorganic
encapsulation layers 142 and 146 are deposited in a low-temperature
atmosphere, it is possible to prevent damage to the light-emitting
stack 124, which is vulnerable to a high-temperature atmosphere,
during the process of depositing the first and second inorganic
encapsulation layers 142 and 146.
[0035] The organic encapsulation layer 144 serves to dampen the
stress between the respective layers due to bending of the organic
light-emitting display device and to increase planarization
performance. The organic encapsulation layer 144 is formed on the
substrate 111, on which the first inorganic encapsulation layer 142
has been formed, using a non-photosensitive organic insulation
material, such as PCL, acrylic resin, epoxy resin, polyimide,
polyethylene or silicon oxycarbide (SiOC), or using a
photosensitive organic insulation material such as photoacryl. The
organic encapsulation layer 144 is disposed in the active area,
rather than the non-active area.
[0036] As illustrated in FIGS. 1 and 2, a touch pad 170 and a
shield pad 180 are disposed in the pad area of the substrate 111
that is exposed by the encapsulation unit 140. The pad area, in
which the touch pad 170 and the shield pad 180 are disposed, can be
bent and disposed on the rear surface of the active area. Thus, the
area occupied by the active area is maximized and the area
corresponding to the pad area is minimized on the entire screen of
the display device.
[0037] The touch pad 170 and the shield pad 180 are disposed on the
portion of the substrate 111 that is exposed by the encapsulation
unit 140. That is, the touch pad 170 and the shield pad 180 are
disposed in the same plane as a display pad, which is connected to
at least one of a scan line or a data line of the pixel-driving
circuit. For example, each of the touch pad 170, the shield pad 180
and the display pad is disposed on a display insulation film of at
least one of the buffer layer 104, the interlayer insulation film
114, the protective film 116 or the planarization film 118, which
is disposed between the substrate 111 and the encapsulation unit
140, or on a touch insulation film 156.
[0038] The touch pad 170 is connected to each of the touch-sensing
line RY and the touch-driving line TX via a touch-routing line 172,
and the shield pad 180 is connected to each of a shield-sensing
line SY and a shield-driving line SX via a shield-routing line
182.
[0039] The shield-routing line 182 and the touch-routing line 172
are disposed along the side surface of the second inorganic
encapsulation layer 146, which is the uppermost layer of the
encapsulation unit 140. Thus, even when external oxygen or moisture
permeates through the touch-routing line 172, the oxygen or
moisture is blocked by the organic encapsulation layer 144 and the
first and second inorganic encapsulation layers 142 and 146,
thereby protecting the light-emitting stack 124 from the oxygen or
moisture.
[0040] The touch-driving line Tx and the touch-sensing line RY,
which are connected to the touch-routing line 172, are disposed
above the active region of the encapsulation unit 140.
[0041] The touch-driving line TX and the touch-sensing line RY form
a mutual capacitance sensor Cm and a self-capacitance sensor Cs.
The mutual capacitance sensor Cm, which is formed at the
intersection between the touch-driving line Tx and the
touch-sensing line RY, charges an electric charge in response to a
first touch-driving signal to be supplied to the touch-driving line
TX, and senses a touch coordinate by discharging the electric
charge to the touch-sensing line RY. The self-capacitance sensor
Cs, which is formed at any one of the touch-driving line TX and the
touch-sensing line RY, charges an electric charge in response to a
second touch-driving signal supplied to any one of the
touch-driving line TX and the touch-sensing line RY, and senses a
touch coordinate by discharging the electric charge through any one
of the touch-driving line TX and the touch-sensing line RY.
[0042] As illustrated in FIGS. 3 and 4A, the touch-driving line TX
includes a plurality of touch-driving electrodes TE and first touch
bridges TB electrically connecting the touch-driving electrodes TE
to each other.
[0043] The touch-driving electrodes TE are spaced apart from each
other at regular intervals in the X-axis direction, which is the
first direction, on the touch insulation film 156. Each of the
touch-driving electrodes TE is electrically connected to an
adjacent touch-driving electrode TE via the first touch bridge
TB.
[0044] The first touch bridge TB is disposed on the second
inorganic encapsulation layer 146 of the encapsulation unit 140,
and is exposed through a contact hole penetrating the touch
insulation film 156 and is electrically connected to the
touch-driving electrodes TE.
[0045] As illustrated in FIGS. 3 and 4B, the touch-sensing line RY
includes a plurality of touch-sensing electrodes RE and second
touch bridges RB electrically connecting the touch-sensing
electrodes RE to each other.
[0046] The touch-sensing electrodes RE are spaced apart from each
other at regular intervals in the Y-axis direction, which is the
second direction, on the touch insulation film 156 in the same
plane as the touch-driving electrodes TE. Each of the touch-sensing
electrodes RE is electrically connected to an adjacent
touch-sensing electrode RE via the second touch bridge RB.
[0047] The second touch bridge RB includes lower and upper touch
bridges 152a and 152b, which are disposed in different planes from
each other.
[0048] The lower touch bridge 152a is disposed on the second
inorganic encapsulation layer 146 of the encapsulation unit in the
same plane as the shield-driving and shield-sensing electrodes SE1
and SE2. The lower touch bridge 152a is exposed through a contact
hole penetrating the touch insulation film 156 and is connected to
the touch-sensing electrode RE.
[0049] The upper touch bridge 152b is disposed on the touch
insulation film 156 in the same plane as the touch-driving
electrode TE so as to cross the touch-driving electrode TE. The
upper touch bridge 152b is disposed so as to be spaced apart from
the touch-driving electrode TE with a separation hole 154
therebetween, thereby preventing the occurrence of a short-circuit
between the touch-driving electrode TE and the upper touch bridge
152b. The upper touch bridge 152b is electrically connected to the
lower touch bridge 152a, which is exposed through a contact hole
penetrating the touch insulation film 156.
[0050] A shield line, which includes the shield-driving line SX and
the shield-sensing line SY, is disposed between each of the
touch-driving line TX and the touch-sensing line RY and the
light-emitting element 120. The shield-driving line SX is disposed
along the touch-driving line TX so as to overlap the touch-driving
line TX, and the shield-sensing line SY is disposed along the
touch-sensing line RY so as to overlap the touch-sensing line RY.
The touch insulation film 156 is disposed between the touch-driving
line TX and the shield-driving line SX and between the
touch-sensing line RY and the shield-sensing line SY.
[0051] As illustrated in FIGS. 3 and 4C, the shield-driving line SX
includes a plurality of shield-driving electrodes SE1 and first
shield bridges SB1 electrically connecting the shield-driving
electrodes SE1 to each other.
[0052] The shield-driving electrodes SE1 are spaced apart from each
other at regular intervals in the X-axis direction, which is the
first direction, on the touch insulation film 156. Each of the
shield-driving electrodes SE1 is electrically connected to an
adjacent shield-driving electrode SE1 via the first shield bridge
SB1.
[0053] The first shield bridge SB1 is disposed on the touch
insulation film 156 in the same plane as the touch-sensing
electrode RE so as to cross the touch-sensing electrode SE. The
first shield bridge SB1 is disposed so as to be spaced apart from
the touch-sensing electrode RE with a separation hole 166
therebetween, thereby preventing the occurrence of a short-circuit
between the touch-sensing electrode RE and the first shield bridge
SB1. The first shield bridge SB1 is electrically connected to the
shield-driving electrodes SE1, which are exposed through a contact
hole penetrating the touch insulation film 156.
[0054] As illustrated in FIGS. 3 and 4D, the shield-sensing line SY
includes a plurality of shield-sensing electrodes SE2 and second
sensing bridges SB2 electrically connecting the shield-sensing
electrodes SE2 to each other.
[0055] The shield-sensing electrodes SE2 are spaced apart from each
other at regular intervals in the Y-axis direction, which is the
second direction, on the second inorganic encapsulation layer 146
in the same plane as the shield-driving electrodes SE1. Each of the
shield-sensing electrodes SE2 is electrically connected to an
adjacent shield-sensing electrode SE2 via the second shield bridge
SB2.
[0056] The second shield bridge SB2 includes lower and upper shield
bridges 162a and 162b, which are disposed in different planes from
each other.
[0057] The lower shield bridge 162a is disposed on the second
inorganic encapsulation layer in the same plane as the
shield-driving and shield-sensing electrodes SE1 and SE2 so as to
cross the shield-sensing electrode SE1. As illustrated in FIG. 4A,
the lower shield bridge 162a is disposed so as to be spaced apart
from the shield-sensing electrode SE1 with a separation hole 164
therebetween, thereby preventing the occurrence of a short-circuit
between the shield-sensing electrode SE1 and the lower shield
bridge 162a. The lower shield bridge 162a is electrically connected
to the upper shield bridge 162b that is exposed through the contact
hole penetrating the touch insulation film 156, as illustrated in
FIG. 4D.
[0058] The upper shield bridge 162b is disposed on the touch
insulation film 156 in the same plane as the touch-sensing
electrode RE.
[0059] At least one of the touch-driving electrodes TE, the
touch-sensing electrodes RE, the shield-driving electrodes SE1 or
the shield-sensing electrodes SE2, which are illustrated in FIGS. 3
to 4D, is formed in a mesh shape. Each of the mesh-shaped
electrodes TE, RE, SE1 and SE2 corresponds to the bank 128 of each
subpixel, and the open area between the meshes of each of the
electrodes TE, RE, SE1 and SE2 corresponds to the emission area of
each subpixel.
[0060] At least one of the first touch bridge TB, the second touch
bridge RB, the first shield bridge SB1 or the second shield bridge
SB2, illustrated in FIGS. 3 to 4D, is disposed so as to overlap the
bank 128, thereby preventing the aperture ratio from being lowered
by the bridges TB, RB, SB1 and SB2.
[0061] When driven in a self-capacitance mode, a load free driving
signal (LFD) is supplied to at least one of the shield-driving line
SX or the shield-sensing line SY. The load free driving signal is
an alternating-current signal of a voltage of which at least one of
the amplitude or the phase is the same as that of the touch-driving
signal to be supplied to at least one of the touch-driving line TX
or the touch-sensing line RY. Thus, because there is no difference
in voltage between the shield lines SX and SY and the touch lines
TX and RY, it is possible to minimize parasitic capacitance between
the shield lines SX and SY and the touch lines TX and RY.
[0062] When driven in a mutual-capacitance mode, the shield-driving
line SX is electrically connected to the touch-driving line TX, or
is switched to a floating state in which no signal is applied
thereto. In addition, when driven in the mutual-capacitance mode,
the shield-sensing line SY is electrically connected to the
touch-sensing line RY, or is switched to a floating state in which
no signal is applied thereto. In particular, during the
mutual-capacitance sensing operation, when the shield-driving line
SX and the touch-driving line TX are electrically connected to each
other and the shield-sensing line SY and the touch-sensing line RY
are electrically connected to each other, the line resistance of
each of the touch-driving line TX and the touch-sensing line RY can
be reduced.
[0063] FIG. 5 is a view illustrating the touch-driving circuit for
driving the touch sensors according to an example of the present
invention.
[0064] The touch-driving circuit 190 illustrated in FIG. 5
determines the presence or absence of a touch and a touch position
by controlling the operation of the touch sensors in the
mutual-capacitance mode and the self-capacitance mode. The
touch-driving circuit 190 includes a multiplexer 192 and a sensing
unit 194.
[0065] In the mutual-capacitance mode, the multiplexer 192
electrically connects a driving power source, for generating a
first touch-driving signal TDM, the touch-driving line TX, and the
shield-driving line SX to each other, and connects the
touch-sensing line RY and the shield-sensing line SY to the sensing
unit 194.
[0066] In the first self-capacitance mode, the multiplexer 192
connects the touch-driving line TX to a driving power source for
generating a second touch-driving signal TDS and connects the
touch-driving line TX to the sensing unit 194. In the first
self-capacitance mode, the multiplexer 192 connects the
shield-driving electrode SX to a driving power source for
generating the load free driving signal LFD corresponding to the
second touch-driving signal TDS.
[0067] In the second self-capacitance mode, the multiplexer 192
connects the touch-sensing line RY to the driving power source for
generating the second touch-driving signal TDS and connects the
touch-sensing line RY to the sensing unit 194. In the second
self-capacitance mode, the multiplexer 192 connects the
shield-sensing electrode SY to the driving power source for
generating the load free driving signal LFD corresponding to the
second touch-driving signal TDS.
[0068] The sensing unit 194 is connected to the touch-sensing lines
RY1 to RYm, the touch-driving lines TX1 to TXn, the shield-sensing
lines SY1 to SYm and the shield-driving lines SX1 to SXn via the
multiplexer 192, and senses variation in potential of the
touch-sensing lines RY1 to RYm, the touch-driving lines TX1 to TXn,
the shield-sensing lines SY1 to SYm and the shield-driving lines
SX1 to SXn.
[0069] FIG. 6A is a view illustrating the mutual-capacitance mode
of the display device having a touch sensor according to an example
of the present invention in detail, FIG. 6B is a view illustrating
the first self-capacitance mode of the display device having a
touch sensor according to an example of the present invention in
detail, and FIG. 6C is a view illustrating the second
self-capacitance mode of the display device having a touch sensor
according to an example of the present invention in detail.
[0070] Referring to FIG. 6A, in the mutual-capacitance mode, the
multiplexer 192 sequentially supplies the first touch-driving
signal TDM to the touch-driving lines TX1 to TXn. The sensing unit
194 senses a touch position by sensing variation in mutual
capacitance through the touch-sensing lines RY1 to RYm. Here, the
multiplexer 194 electrically connects the shield-driving electrodes
SX1 to SXn to the touch-driving lines TX1 to TXn and electrically
connects the shield-sensing lines SY1 to SYm to the touch-sensing
lines RY1 to RYm. Thus, the line resistance of each of the
touch-driving lines TX1 to TXn and the touch-sensing lines RY1 to
RYm can be reduced.
[0071] Referring to FIG. 6B, in the first self-capacitance mode,
the multiplexer 192 sequentially supplies the second touch-driving
signal TDS to the touch-driving lines TX1 to TXn. The sensing unit
194 senses a touch position by sensing variation in the potential
of the touch-driving lines TX1 to TXn in response to the second
touch-driving signal.
[0072] While the second touch-driving signal TDS is supplied to the
touch-driving lines TX1 to TXn, the load free driving signal LFD is
supplied to the shield-driving lines SX1 to SXn, which overlap the
touch-driving lines TX1 to TXn. Since the load free driving signal
LFD has the same amplitude and phase as the first touch-driving
signal TDS, there is no difference in voltage between the
touch-driving electrode TX and the shield-driving electrode SX in
the first self-capacitance mode. Thus, it is possible to minimize
the parasitic capacitance between the touch-driving electrode TX1
and the shield-driving electrode SX1, thereby preventing the
generation of noise for a first self-capacitance mode period.
[0073] The multiplexer 192 supplies a ground voltage GND to the
touch-sensing lines RY1 to RYm and the shield-sensing lines SY1 to
SYm. The touch-sensing lines RY1 to RYm and the shield-sensing
lines SY1 to SYm, to which the ground voltage GND is supplied,
block noise generated from the light-emitting element 120 and the
pixel-driving circuit, thereby improving touch-sensing performance.
In addition, the multiplexer 192 can create a floating state, in
which no signal is applied to the touch-sensing lines RY1 to RYm or
to the shield-sensing lines SY1 to SYm.
[0074] Referring to FIG. 6C, in the second self-capacitance mode,
the multiplexer 192 sequentially supplies the second touch-driving
signal TDS to the touch-sensing lines RY1 to RYm. The sensing unit
194 senses a touch position by sensing variation in the potential
of the touch-sensing lines RY1 to RYm in response to the second
touch-driving signal TDS.
[0075] While the second touch-driving signal TDS is supplied to the
touch-sensing lines RY1 to RYm, the load free driving signal LFD is
supplied to the shield-sensing lines SY1 to SYm, which overlap the
touch-sensing lines RY1 to RYm. Since the load free driving signal
LFD has the same amplitude and phase as the second touch-driving
signal TDS, there is no difference in voltage between the
touch-sensing electrode RY and the shield-sensing electrode SY in
the second self-capacitance mode. Thus, it is possible to minimize
the parasitic capacitance between the touch-sensing electrode RY
and the shield-sensing electrode SY, thereby preventing the
generation of noise for a second self-capacitance mode period.
[0076] The multiplexer 192 supplies a ground voltage GND to the
touch-driving lines TX1 to TXn and the shield-driving lines SX1 to
SXn. The touch-driving lines TX1 to TXn and the shield-driving
lines SX1 to SXn, to which the ground voltage GND is supplied,
block noise generated from the light-emitting element 120 and the
pixel-driving circuit, thereby improving touch-sensing performance.
In addition, the multiplexer 192 can create a floating state, in
which no signal is applied to the touch-driving lines TX1 to TXn or
to the shield-driving lines SX1 to SXn.
[0077] FIG. 7 is a waveform diagram illustrating the signal
waveform to be supplied during one frame period in the display
device having a touch sensor according to an example of the present
invention.
[0078] Referring to FIG. 7, one frame period 1F is time-divided
into a display period DP and a touch-sensing period TP. One
touch-sensing period TP is allocated between the display periods
DP.
[0079] During the display period DP, a pixel-driving signal (e.g.,
a scan signal, a data signal, a low-voltage driving signal, and a
high-voltage driving signal) is supplied to each subpixel. Here,
the scan signal is the voltage of a gate pulse to be supplied to
each scan line. The data signal is the data voltage of an input
image to be supplied to each data line during the display period.
The low-voltage driving signal is the voltage to be supplied to the
cathode of each light-emitting element 120 during the display
period DP. The high-voltage driving signal is the voltage to be
supplied to the drain electrode of each driving transistor during
the display period DP. During the display period DP, the touch
electrode can be switched to a floating state in which no signal is
applied thereto or to a state in which a specific voltage (e.g.,
ground voltage) is applied thereto.
[0080] During the touch-sensing period TP, the touch-driving
circuit 190 selectively supplies the touch-driving signals TDM and
TDS and the load free driving signal LFD to the touch-sensing lines
RY1 to RYm, the touch-driving lines TX1 to TXn, the shield-sensing
lines SY1 to SYm and the shield-driving lines SX1 to SXn in
response to a touch control signal Tsync received from the timing
controller.
[0081] Specifically, as illustrated in FIG. 8, the touch-sensing
period TP is time-divided into a mutual-capacitance mode period TMP
and a self-capacitance mode period TSP.
[0082] During the mutual-capacitance mode period TMP, the first
touch-driving signal TDM is sequentially supplied to the
touch-driving electrodes TX1 to TXn. Subsequently, the sensing unit
senses a touch position by sensing variation in the potential of
the touch-sensing electrodes RY1 to RYm. At this time, the first
touch-driving signal TDM is also supplied to the shield-driving
electrodes SX1 to SXn, which were electrically connected to the
touch-driving electrodes TX1 to TXn.
[0083] During the self-capacitance mode period TSP, the second
touch-driving signal TDS is sequentially supplied to the
touch-driving lines TX1 to TXn. While the second touch-driving
signal TDS is supplied to the touch-driving lines TX1 to TXn, the
load free driving signal LFD is supplied to the shield-driving
lines SX1 to SXn, which overlap the touch-driving lines TX1 to TXn.
Subsequently, the second touch-driving signal TDS is sequentially
supplied to the touch-sensing lines RY1 to RYm. While the second
touch-driving signal TDS is supplied to the touch-sensing lines RY1
to RYm, the load free driving signal LFD is supplied to the
shield-sensing lines SY1 to SYm, which overlap the touch-sensing
lines RY1 to RYm.
[0084] Thus, it is possible to minimize the parasitic capacitance
between each of the touch-driving lines TX1 to TXn and the
touch-sensing lines RY1 to RYm and the electrodes of the
light-emitting element, thereby removing touch noise and
consequently increasing touch-sensing accuracy.
[0085] Although the light-emitting element 120 and the
pixel-driving circuit may not be illustrated in FIGS. 4A to 4D, a
plurality of light-emitting elements 120 and pixel-driving circuits
can be disposed under the encapsulation unit 140, as illustrated in
FIG. 2.
[0086] As is apparent from the above description, according to the
present invention, a shield electrode is disposed between each of a
touch-sensing line and a touch-driving line and a light-emitting
element. While a touch-driving signal of a self-capacitance mode is
applied to at least one of the touch-sensing line or the
touch-driving line, a load free driving signal, of which at least
one of the phase or the amplitude is the same as that of the
touch-driving signal, is supplied to the shield line. As a result,
it is possible to remove touch noise and consequently to secure
improved touch-sensing performance.
[0087] It will be apparent to those skilled in the art that various
modifications and variations can be made in the present invention
without departing from the spirit or scope of the invention. Thus,
it is intended that the present invention covers the modifications
and variations of this invention provided they come within the
scope of the appended claims and their equivalents.
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